Why East African region is at risk of animal diseases transmitted to humans

Arusha. The East African region is at risk of zoonotic diseases, including those from wild animals, experts have warned.

They are likely to be fuelled by the increasing temperatures which are favourable for the transmission of pathogens.

With the abundance of free-ranging livestock and wildlife and interfaces with humans, the transmission risks could be much higher.

This is according to a report released by Traffic, a global NGO which doubles as a wildlife trade monitoring network.

Zoonotic diseases are infectious diseases that are naturally transmitted between animals and humans.

The tropical climate in East Africa hosts favourable conditions for transmission risks of various zoonotic diseases.

Dr Daniel Mdetele, a veterinary expert, says zoonotic diseases do not only lead to morbidities and mortalities but disrupt trade.

"As it was during the recent Covid-19, zoonotics negatively impacted the economy in developing and developed countries," he said.

Illegal wildlife trade increases the risk of zoonotic disease transmission due to spill over from wildlife to domestic animals and humans.

Dr Mdetele, an epidemiologist from the Tanzania Veterinary Service, wants a multi-pronged approach to contain the diseases.

These have to include investment in healthcare infrastructure, veterinary services and public health systems.

Recently reported zoonotic disease outbreaks in East Africa include Marburg virus in Tanzania and Ebola in Uganda in March and January this year respectively.

"These viruses are highly contagious and can cause severe illness, often with high mortality rates", the vet expert said in a report seen by The Citizen.

The reported leptospirosis outbreak in southern Tanzania is another contemporary example of zoonotic diseases of concern in the EA region.

Over the years, the region has been struggling with a variety of zoonotic diseases, including rabies, brucellosis, and anthrax.

Others are Rift Valley Fever, bovine tuberculosis, porcine cysticercosis, African trypanosomiasis, salmonellosis, and borreliosis.

He expressed much concern on zoonotic diseases from the wild animals to humans which are often downplayed or neglected.

Transporting wild animals and their products are among activities which predispose humans to zoonotic disease risks.

Markets selling the meat or by-products of wild animals are particularly at high risk due to the substantial number of new or undocumented pathogens.

These are pathogens known to exist in some wild animal populations, including those that co-exist with livestock and other domesticated species.

The most common animal species that are reservoirs for zoonotic diseases include non-human primates, bats, rodents, small carnivores, swine, rabbits, and dogs.

Historical global pandemics such as HIV/Aids and Ebola both originated in Africa, and the first HIV/Aids cases were reported in Zaire (now DR Congo).

The first human HIV infection dates from 1959, while Aids, later recorded and recognised as a disease in 1981, evolved from non-human primates in and around East Africa.

Outbreaks of the Ebola virus near DR Congo's Ebola River in 1976 and then followed by an outbreak in a geographic area that is now South Sudan.

According to experts working with the Traffic office in Arusha, a project is underway to reduce zoonotic disease risks in trade.

The project will be undertaken with the support of the American and German aid agencies; USAID and GIZ respectively.

A number of wild animal species in the region are killed for meat consumption by the locals and meat trade whether legal or illegal.

The project outputs aim to support the East Africa Community (EAC) secretariat in its One Health Action plan to minimise future zoonotic pandemic risks.

Traffic is also working in northern Tanzania on social and behavioural change activities to reduce poaching of wildlife and illegal consumption of wild meat.

According to the experts, the latter (consumption of wild meat) poses a significant threat to public health.

A report issued by the World Health Organisation (WHO) last year shows that diseases transmitted from animals to people in Africa have jumped 63 per cent in the last decade.

Other experts say zoonotic diseases represent approximately 32 percent of Africa's infectious disease outbreak reported between 2001 and 2022.

“And more than 75 percent of emerging infectious diseases are are caused by pathogens shared with wild or domestic animals,” WHO regional director for Africa Matshidiso Moeti told journalists.

“They account for a substantial burden of diseases, resulting in about a billion sick people, and millions of deaths globally every year”.

The analysis finds that since 2001, 1,843 substantiated public health events were recorded in the African region – 30 per cent of which were zoonotic outbreaks, as animal-to-human diseases are known. While the numbers have increased over the past two decades, 2019 and 2020 saw a particular spike, with zoonotic pathogens accounting for half of all public health events.

Moreover, Ebola and similar fevers triggering blood loss from damaged vessels (haemorrhagic) constitute nearly 70 percent of these outbreaks, including Monkeypox, Dengue fever, anthrax and plague.